Commercial variations or checks in molded containers such as glass bottles and jars are often related to anomalies in the associated molds of origin For this reason, it is desirable in an automated operation having a plurality of molds to possess the ability of identifying a specific molded container with its mold of origin A mold associated with anomalous containers may then be shut down for repair while the remaining molds continue operation Alternatively, containers from the anomalous mold may be automatically sorted as they proceed along the production line.
Mold identification is generally accomplished by molding a mold-identifying code into each container during the forming process. This code may be read by a suitable scanner for identifying the container with its mold of origin U.S. Pat. No. 4,644,151 discloses a system in which each container has molded therein a plurality of indicia in the form of surface irregularities (bumps or protrusions) extending in a arcuate array around the container heel perpendicularly of the container axis. A source of semi-diffused light energy is directed onto the container heel as the container is rotated about its central axis, with the light energy source having an intensity gradient at predetermined orientation with respect to the container axis. A camera, which includes a linear array of light elements optically coplanar with the container axis, is positioned to receive an image of the light source reflected by the container heel, such that individual irregularities in the code array alter the intensity of light reflected by the heel onto the camera. An information processor receives electrical signals from the camera associated with intensity of light at the various camera elements, and the code is read as a function of alterations in light intensity caused by reflections from the bump side edges.
Although the apparatus disclosed in the noted U.S. Patent represents a significant advance in the art theretofore developed, further improvements remain desirable. For example, use of reflected light energy in the preferred embodiment of the disclosed apparatus makes alignment and setup of apparatus components somewhat critical, and necessitates resetup for containers of differing sizes and/or having bumps or protrusions of differing geometries. Further, in the preferred embodiment of the disclosed apparatus, the containers are held stationary and rotated about their central axes to sweep the heel codes across the light source, thereby necessitating interruption of continuous motion of the containers through the production facility. It is a general object of the present invention to provide an apparatus and method for reading a mold-identifying code on a container of the described character that are adapted to operate as the container is fed in a continuous uninterrupted motion through the apparatus code-reading station, and/or that employ an image of the light source that is transmitted through rather then reflected by the container, thereby rendering apparatus setup less sensitive to size and shape of the containers and/or the code-identifying irregularities.